The track bushings used in the track pins for linking the track links for the endless track of a track type vehicle, such as an earthmoving vehicle for example, are subjected to a very severe operating environment. The ends of the track bushing and the inner surface of the track bushing adjacent its two ends are the main bearing surfaces that respectively slide against the track seal and the track pin. The dirt and debris tend to wear the ends of the track bushings sliding against the sealing surface of a track seal. This happens because the dirt and debris particles get lodged between the seal and the bushing end surface and eventually wear a groove into the track bushing end. The formation of a wear groove causes oil to leak out of the pin joint assembly leading to an eventual failure of the joint.
It is desirable to provide a track bushing that has a very hard, highly corrosion resistant coating on its ends that protects the track bushing ends from corrosion and erosion. It is also very desirable to provide a track bushing having very high resistance to groove formation on its ends when the ends are biased against a track seal. It is further desirable to deposit a hard coating within a preformed groove in the track bushing end to provide substantial improvement in the longevity of wear resistance. It is yet further desirable to provide a process for depositing a hard coating within a preformed groove so that not only is there a very strong bond between the substrate and the coating but that there is a least amount of dilution of the substrate metal and the coating metal. It is also desirable to provide a process whereby a hard coating can be deposited in a manner desired above without any appreciable tempering of the bushing metal.
The present invention is directed to overcome one or more problems of heretofore utilized track bushings for track-type vehicles.